Antioxidant chitosan-based biocomposite fabricated from crustacean shell-derived fractions

The exoskeleton of crustaceans containing chitin, minerals, carotenoids and proteins is naturally synthesized to provide mechanical and bioactive properties. This work involves the extraction of chitin and lipidic fractions present in shrimp shells, which exert structural and antioxidant functions, to assemble them into a functional biocomposite. The isolated chitin was used as chitosan precursor to render structural support to the bioactive molecules. The lipidic fraction, comprising astaxanthin and proteins, contributes to antioxidation and stability, respectively. Minerals were replaced with glycerol to confer flexibility to the resulting material. The casted films (43% chitosan, 36% lipidic fraction, 21% glycerol) with a thickness of 75 µm exhibited mechanical properties suitable for packaging applications. The embedded lipidic fraction imparted antioxidant capacity to the material, proved by the DPPH radical scavenging ability, with more than 60% of the initial activity retained after 4 weeks of storage. The performance of the films was tested on the evolution of lipid oxidation of meat samples stored at ambient conditions. The film containing the lipidic fraction effectively delayed lipid oxidation, maintaining malondialdehyde (MDA) levels about 25% lower after 7 days compared to films lacking the antioxidant component.